To view cluster metrics, expand the Details section of the Cassandraprocess group.

Click the Process group details button.

On the Process group details page, select the Technology-specific metrics tab, where you can identify problematic nodes.

Select a relevant time interval from the Time frame selector in the top menu bar.

Select a metric type from the metric drop list beneath the timeline to compare the values of all nodes in a sortable table view.

To access node-specific metrics, select a node from the Process list at the bottom of the page.

Click the Cassandrametrics tab. Here you’ll find valuable Cassandra node-specific metrics. The Exceptions and Failed requests charts show you if there’s a problem with the node. Pay particular attention to Unavailable Read/Write/RangeSlice counts. Increased latency while the number of operations remains stable typically indicates a performance issue.

Cassandra node metrics

Metric

Chart

Description

Exception count

Exceptions

Number of internal Cassandra exceptions detected. Under normal conditions, this metric should be zero.

Unavailable – Read

Failed requests

Number of Unavailable – Read exceptions encountered

Unavailable – Write

Failed requests

Number of Unavailable – Write exceptions encountered

Failed requests

Number of Unavailable – RangeSlice exceptions encountered

Timeout – Read

Failed requests

Number of Timeout – Read exceptions encountered

Timeout – Write

Failed requests

Number of Timeout – Write exceptions encountered

Timeout – RangeSlice

Failed requests

Number of Timeout – RangeSlice exceptions encountered

Failure – Read

Failed requests

Number of read failure exceptions encountered

Failure – Write

Failed requests

Number of Failure – Read exceptions encountered

Failure – RangeSlice

Failed requests

Number of Failure – RangeSlice exceptions encountered

Read

Operation count

Adverage number or Reads per second

Write

Operation count

Adverage number or Writes per second

RangeSlice

Operation count

Adverage number or RageSlices per second

Read

Latency 95th percentile

Average 95th percentile of transaction read latency

Write

Latency 95th percentile

Average 95th percentile of transaction write latency

RangeSlice

Latency 95th percentile

Average 95th percentile of transaction RangeSlice latency

Additional Cassandra node monitoring metrics

More Cassandra monitoring metrics are available on individual Process pages. Select the Further details tab to view these metrics.

Here you’ll find six tabs and plenty of informative metrics.

The Cache tab tells you about the Row cache and Key cache hit rates. The Disk usage tab provides essential understanding of the health of the Cassandra compaction process. On the Load tab you’ll find details about ongoing and past operations. Above-average Maximum latency measurements may indicate that you have some very slow requests. Charts on the Thread Poolstab should be empty, or at least be very low. A continuously high number of pending reads indicates a problem. For full details, see Pending task metrics for reads.

Additional Cassandra metrics

Metric

Chart

Description

Disk space

Total disk space used

Total disk space used by SSTables, including obsolete tables waiting to be GC’d

Row cache hit rate

Hit rate

2m row cache hit rate

Key cache hit rate

Hit rate

2m key cache row hit rate

Load

Storage load

Size, in bytes, of the on-disk data the node manages

Bytes compacted

Bytes compacted

Total number of bytes compacted since server start

Pending tasks

Compaction tasks pending

Estimated number of compactions remaining to perform

Completed tasks

Compaction tasks completed

Number of completed compactions since server start

SSTable count

SSTable count

Number of SSTables on disk for this table

Hints

Hints

Number of hint messages written to this node since start. Includes one entry for each host to be hinted per hint

Want to learn more?

Have feedback?

Your feedback about Dynatrace Cassandra monitoring is most welcome! Let us know what you think of the new Cassandra plugin by adding a comment below. Or post your questions and feedback to Dynatrace Answers.

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